I got a pair of the Next jersey tapered trousers for £18 the other day to wear on the plane. They don't crease when wearing and I haven't sweated in them yet - though it's hardly been roasting where I am but they do seem non-sweaty. I got plain black ones but they have loads of different patterned ones.

I also got a pair of black jersey wide legged cropped trousers from there recently too which I'm planning on taking on hols. I don't normally get much from Next/find a lot that I like but I'm pleased with those 2 purchases.